In one embodiment, the present disclosure relates to the evolved enhanced general packet radio service (EGPRS2), and in particular to IDFT precoded EGPRS2 (PCE2). The examples given in the present disclosure relate to EGPRS2 and PCE2. However, this is not meant to be limiting and EGPRS2 and PCE2 are merely examples of communication techniques.
PCE2 is an ongoing study item currently being investigated in 3GPP GERAN (GSM/EDGE radio access network). PCE2 is a new feature that is meant to improve link level performance of the EGPRS2, which results in an increase in throughput or an enhancement of coverage by applying an inverse discrete Fourier transform (IDFT) precoding technique. As will be appreciated by those in the art having regard to the present disclosure, the IDFT precoding technique may be considered an orthogonal frequency division multiplexing (OFDM) technique.
PCE2 reduces the complexity of channel equalization at the receiver so that the receiver can avoid performance loss due to the simplification of equalization for radio channels for higher order modulations. To allow minimal changes to the standards and implementation, PCE2 preserves most of the modulation and coding schemes (MCSs) of EGPR2.
One drawback to the use of an IDFT precoder at a transmitter is a significant increase in the peak-to-average power ratio (PAPR) value. Compared to EGPRS2, in PCE2 the PAPR values may be up to 8.25 dB or higher with the probability of 10−4. As will be appreciated by those in the art, this reduces the efficiency of the transmitter power amplifier due to the requirement of the large back off of the power amplifier to satisfy the requirements of spectral mask and adjacent channel power leakage, among others. The above is described, for example, in the Third Generation Partnership Project (3GPP) “Radio Transmission and Reception”, Technical specification (TS) 45.005, v.9.5.0, Dec. 21, 2010, the contents of which are incorporated herein by reference.